I was motivated to improve the U.S. strategy of going back to the moon in 1985. That's a long time ago. Going back to the moon would be a great achievement for tourism adventure flights.
There's a historical milestone in the fact that our Apollo 11 landing on the moon took place a mere 66 years after the Wright Brothers' first flight.
Bringing an asteroid back to Earth? What's that have to do with space exploration? If we were moving outward from there, and an asteroid is a good stopping point, then fine. But now it's turned into a whole planetary defense exercise at the cost of our outward exploration.
Nobody cares about the bronze or silver medals.
You need propellants to accelerate toward Mars, then to decelerate at Mars, again to re-accelerate from Mars to Earth, and finally to decelerate back at Earth. Accordingly, the mass of these required propellants, in short, drives our need for innovative launch vehicles.
There are always door openings. And gradually, it accumulates. The opportunities open up in front of you.
My favourite thing to do on this planet is to scuba dive.
As we reflect back upon the tragic loss of Challenger and her brave crew of heroes who were aboard that fateful day, I am reminded that they truly represented the best of us, as they climbed aloft on a plume of propellant gasses, reaching for the stars, to inspire us who were Earthbound.
If we can conquer space, we can conquer childhood hunger.
I think the American Dream used to be achieving one's goals in your field of choice - and from that, all other things would follow. Now, I think the dream has morphed into the pursuit of money: Accumulate enough of it, and the rest will follow.
I was the first Navy, Marine or Air Force person who had been an astronaut to return back to the Air Force. I had certain expectations about what would be a reasonable and desirable position to be assigned to after my years of service.
There's a need for accepting responsibility - for a person's life and making choices that are not just ones for immediate short-term comfort. You need to make an investment, and the investment is in health and education.
Maybe it was the challenge of flight, the opportunity to fly, the competition of summer camp and the inspiration and discipline of West Point. I think all of those things helped me to develop a dedication and inspired me to get ahead.
Timing has always been a key element in my life. I have been blessed to have been in the right place at the right time.
Whenever I gaze up at the moon, I feel like I'm on a time machine. I am back to that precious pinpoint of time, standing on the foreboding - yet beautiful - Sea of Tranquility. I could see our shining blue planet Earth poised in the darkness of space.
If we go back to the moon, we're guaranteed second, maybe third place because while we are spending all that money, Russia has its eye on Mars. Landing people on the moon will be terribly consuming of resources we don't have. It sounds great - 'Let's go back. This time we're going to stay.' I don't know why you would want to stay on the moon.
I've led a life of such structured discipline and always had a goal in mind of knowing what I was doing, from West Point to the Air Force combat, MIT, looking for new things to study and get involved in. And then I got into the space program, and how disciplined can you get?
There may be aliens in our Milky Way galaxy, and there are billions of other galaxies. The probability is almost certain that there is life somewhere in space.
We must still think of ourselves as pioneers to understand the importance of space.
I still say, 'Shoot for the moon; you might get there.'